PURPOSE: To determine whether premedication with a beta-blocker can bring about a more rapid and smooth induction of anesthesia, we investigated the effect of oral premedication with atenolol on volatile anesthetic induction with sevoflurane by monitoring the cardiac output (CO) and bispectral (BIS) index. METHODS:Twenty-four patients undergoing general anesthesia with endotracheal intubation were randomly divided into two groups: a control group ( n = 12) and a beta-blocker group ( n = 12). Each patient in the beta-blocker group was premedicated with oral atenolol 25 mg 1 h before the induction of anesthesia. Anesthesia was induced by the repeated vital capacity technique with 5% sevoflurane and 66% nitrous oxide. The trachea was intubated 5 min after sevoflurane exposure. The CO and BIS index, as well as the induction time and specific side effects of induction (e.g., movement of limbs), were recorded. RESULTS: There were no significant differences in induction time and specific side effects between the groups. The downward-sloping part of the BIS index curve in the beta-blocker group (mean, 2.9 +/- 0.2) was significantly sharper than that in the control group (2.5 +/- 0.2), and the BIS index after induction of anesthesia was significantly lower in the beta-blocker group (21.0 +/- 2.2) than in the control group (24.2 +/- 2.0). CO in the beta-blocker group was significantly lower than in the control group during the study period. The hemodynamic changes caused by endotracheal intubation were inhibited in the beta-blocker group but not in the control group. CONCLUSION: Oral premedication with 25 mg of atenolol provides a more rapid decrease in BIS index and is recommended for use in stable volatile anesthetic induction with sevoflurane.
RCT Entities:
PURPOSE: To determine whether premedication with a beta-blocker can bring about a more rapid and smooth induction of anesthesia, we investigated the effect of oral premedication with atenolol on volatile anesthetic induction with sevoflurane by monitoring the cardiac output (CO) and bispectral (BIS) index. METHODS: Twenty-four patients undergoing general anesthesia with endotracheal intubation were randomly divided into two groups: a control group ( n = 12) and a beta-blocker group ( n = 12). Each patient in the beta-blocker group was premedicated with oral atenolol 25 mg 1 h before the induction of anesthesia. Anesthesia was induced by the repeated vital capacity technique with 5% sevoflurane and 66% nitrous oxide. The trachea was intubated 5 min after sevoflurane exposure. The CO and BIS index, as well as the induction time and specific side effects of induction (e.g., movement of limbs), were recorded. RESULTS: There were no significant differences in induction time and specific side effects between the groups. The downward-sloping part of the BIS index curve in the beta-blocker group (mean, 2.9 +/- 0.2) was significantly sharper than that in the control group (2.5 +/- 0.2), and the BIS index after induction of anesthesia was significantly lower in the beta-blocker group (21.0 +/- 2.2) than in the control group (24.2 +/- 2.0). CO in the beta-blocker group was significantly lower than in the control group during the study period. The hemodynamic changes caused by endotracheal intubation were inhibited in the beta-blocker group but not in the control group. CONCLUSION: Oral premedication with 25 mg of atenolol provides a more rapid decrease in BIS index and is recommended for use in stable volatile anesthetic induction with sevoflurane.